GB2156852A - Electrolyte for anodisation of aluminium or for electrolytic capacitors - Google Patents
Electrolyte for anodisation of aluminium or for electrolytic capacitors Download PDFInfo
- Publication number
- GB2156852A GB2156852A GB08508118A GB8508118A GB2156852A GB 2156852 A GB2156852 A GB 2156852A GB 08508118 A GB08508118 A GB 08508118A GB 8508118 A GB8508118 A GB 8508118A GB 2156852 A GB2156852 A GB 2156852A
- Authority
- GB
- United Kingdom
- Prior art keywords
- electrolyte
- amino acid
- electrolyte according
- aluminium
- acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000003792 electrolyte Substances 0.000 title claims description 76
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims description 22
- 239000004411 aluminium Substances 0.000 title claims description 22
- 229910052782 aluminium Inorganic materials 0.000 title claims description 22
- 238000002048 anodisation reaction Methods 0.000 title claims description 17
- 239000003990 capacitor Substances 0.000 title claims description 16
- 235000001014 amino acid Nutrition 0.000 claims description 18
- 150000001413 amino acids Chemical class 0.000 claims description 17
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical group OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 16
- CKLJMWTZIZZHCS-REOHCLBHSA-N L-aspartic acid Chemical compound OC(=O)[C@@H](N)CC(O)=O CKLJMWTZIZZHCS-REOHCLBHSA-N 0.000 claims description 16
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical group N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 10
- 239000002904 solvent Substances 0.000 claims description 10
- 235000003704 aspartic acid Nutrition 0.000 claims description 7
- OQFSQFPPLPISGP-UHFFFAOYSA-N beta-carboxyaspartic acid Natural products OC(=O)C(N)C(C(O)=O)C(O)=O OQFSQFPPLPISGP-UHFFFAOYSA-N 0.000 claims description 7
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 6
- GOJUJUVQIVIZAV-UHFFFAOYSA-N 2-amino-4,6-dichloropyrimidine-5-carbaldehyde Chemical group NC1=NC(Cl)=C(C=O)C(Cl)=N1 GOJUJUVQIVIZAV-UHFFFAOYSA-N 0.000 claims description 5
- 150000001412 amines Chemical class 0.000 claims description 5
- 229910021529 ammonia Inorganic materials 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 5
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 claims description 4
- 238000007743 anodising Methods 0.000 claims description 4
- WHUUTDBJXJRKMK-UHFFFAOYSA-N Glutamic acid Natural products OC(=O)C(N)CCC(O)=O WHUUTDBJXJRKMK-UHFFFAOYSA-N 0.000 claims description 3
- WHUUTDBJXJRKMK-VKHMYHEASA-N L-glutamic acid Chemical compound OC(=O)[C@@H](N)CCC(O)=O WHUUTDBJXJRKMK-VKHMYHEASA-N 0.000 claims description 3
- 235000013922 glutamic acid Nutrition 0.000 claims description 3
- 239000004220 glutamic acid Substances 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 claims description 2
- HPNMFZURTQLUMO-UHFFFAOYSA-N diethylamine Chemical compound CCNCC HPNMFZURTQLUMO-UHFFFAOYSA-N 0.000 claims description 2
- 239000011888 foil Substances 0.000 claims description 2
- 235000010210 aluminium Nutrition 0.000 claims 7
- QUSNBJAOOMFDIB-UHFFFAOYSA-N Ethylamine Chemical group CCN QUSNBJAOOMFDIB-UHFFFAOYSA-N 0.000 claims 2
- 239000002253 acid Substances 0.000 claims 1
- 229940024606 amino acid Drugs 0.000 description 11
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 10
- 238000005755 formation reaction Methods 0.000 description 10
- 229940009098 aspartate Drugs 0.000 description 9
- 239000010410 layer Substances 0.000 description 8
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 description 6
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 description 6
- 235000019837 monoammonium phosphate Nutrition 0.000 description 6
- KRKNYBCHXYNGOX-UHFFFAOYSA-K Citrate Chemical compound [O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O KRKNYBCHXYNGOX-UHFFFAOYSA-K 0.000 description 4
- WNLRTRBMVRJNCN-UHFFFAOYSA-L adipate(2-) Chemical compound [O-]C(=O)CCCCC([O-])=O WNLRTRBMVRJNCN-UHFFFAOYSA-L 0.000 description 3
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical class OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 239000005030 aluminium foil Substances 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- -1 for example Chemical class 0.000 description 2
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- YEJRWHAVMIAJKC-UHFFFAOYSA-N 4-Butyrolactone Chemical compound O=C1CCCO1 YEJRWHAVMIAJKC-UHFFFAOYSA-N 0.000 description 1
- FLDCSPABIQBYKP-UHFFFAOYSA-N 5-chloro-1,2-dimethylbenzimidazole Chemical compound ClC1=CC=C2N(C)C(C)=NC2=C1 FLDCSPABIQBYKP-UHFFFAOYSA-N 0.000 description 1
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
- 239000001741 Ammonium adipate Substances 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 1
- 239000001361 adipic acid Substances 0.000 description 1
- 235000011037 adipic acid Nutrition 0.000 description 1
- 235000019293 ammonium adipate Nutrition 0.000 description 1
- 239000000908 ammonium hydroxide Substances 0.000 description 1
- 239000010407 anodic oxide Substances 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 150000001734 carboxylic acid salts Chemical class 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 150000001860 citric acid derivatives Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 150000003947 ethylamines Chemical class 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 229940095064 tartrate Drugs 0.000 description 1
- 150000003892 tartrate salts Chemical class 0.000 description 1
- YWYZEGXAUVWDED-UHFFFAOYSA-N triammonium citrate Chemical compound [NH4+].[NH4+].[NH4+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O YWYZEGXAUVWDED-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
- C25D11/10—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing organic acids
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Electrolytic Production Of Metals (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
- Electric Double-Layer Capacitors Or The Like (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
Description
1 GB 2 156 852A 1
SPECIFICATION
Electrolyte for use in the anodisation of aluminium The present invention is concerned with electrolytes for use in the anodisation of aluminium and, more particularly, with electrolytes which can be used to anodise aluminium to form a low voltage (0- 12 5V) barrier layer of dielectric oxide on the surface of the aluminium or as fill electrolytes in low voltage (0-63V) aluminium electrolytic capacitors.
Salts of carboxylic acids have been used as solutes in the aluminium electrolytic capacitor industry. Aqueous solutions of carboxylic acid salts, for example, citrates, tartrates, and adipates, have been used as anodisation or formation electrolytes, while these compounds and others have been used in non-aqueous operating or fill electrolytes in aluminium electrolytic capacitors.
We have now developed an electrolyte which can be used to form a stable, high capacitance layer of anodic oxide on aluminium and which is suitable for use both as an anodisation electrolyte and as an operating or fill electrolyte in aluminium electrolytic capacitors.
According to the present invention, there is provided an electrolyte for use in the anodisation of aluminium and/or as an operating electrolyte for aluminium electrolytic capacitors, which comprises an amino acid and a base dissolved in a solvent and having a pH of from 5.5 to 8.5.
The amino acid is preferably a 2-amino acid, more preferably a dicarboxylic acid, such as aspartic acid or glutamic acid. The solvent may be water which is commonly used in anodisation electrolytes, or one of the known organic solvents used in electrolytic capacitor fill electrolytes, such as ethylene glycol, N,Ndimethylformamide, 4- butyrolactone, and Nmethylpyrrolidi none.
When the electrolyte of the invention is used as an anodisation electrolyte, the layer of oxide formed on the surface of the aluminium is at least partially crystalline. The capacitance of the layer is higher than that obtained using 115 known anodising electrolytes, such as dilute aqueous ammonium dihydrogen phosphate, which do not produce a layer containing much crystalline oxide. The increased capaci- tance appears to be associated with an increase in the ratio of crystalline to amorphous oxide in the layer.
The highest capacitance is obtained in different electrolytes at different voltages, de- pending on the nature of the solute and the current efficiency of oxide formation. Thus in electrolytes which contain aspartic acid, the highest capacitance is obtained at a lower voltage than in other electrolytes, such as those containing adipic acid, and a higher degree of hydration resistance is obtained.
The formation efficiency of the electrolyte of the present invention is higher than that of other electrolytes, such as citrate and tartrate, which are known to produce a layer containing a comparable amount of crystalline oxide; thus it is possible to use the electrolyte of the invention to anodise aluminium to a higher surface capacitance within a reasonable amount of time.
When a solution of the amino acid in a nonaqueous capacitor solvent is used as a fill electrolyte, the formation rate is still satisfactory for repairing breakdown of the oxide layer during capacitor operation.
The electrolyte is found to give the best results when the amino acid is partially neutrafised with a base to give a pH of from 5.5 to 8.5. When the electrolyte is to be used as a formation electrolyte, the base is preferably ammonia, sodium hydroxide, or potassium hydroxide. However, if the formation is to be carried out at an elevated temperature, an amine which is less volatile than ammonia may be used as the base. In this connection, the ethylamines (mono-, di-, and triethylamines) have proved satisfactory. When the electrolyte is to be used as a fill electrolyte in a capacitor, then ammonia or an amine is pre- ferably used to partially neutralise the amino acid.
When the electrolyte is to be used as an anodisation electrolyte, an aqueous solution of a 2-amino acid is preferred. Particularly pre- ferred 2-amino acids are the amino analogues of 2-hydroxy carboxylic acids which are known to be suitable for anodising aluminium, and specifically aspartic acid and glutamic acid.
Similarly, for fill electrolytes in capacitors, amino acid analogues of hydroxy carboxylic acids are suitable and have sufficient solubility in the organic solvents commonly used in capacitors.
For use as an anodisation electrolyte, the concentration of amino acid is preferably from 0.05 to 5 wt.%, the usual concentration range for such electrolytes; while for use as a fill electrolyte, the concentration of amino acid is preferably higher and is preferably from 5 to 10 wt.%.
In order that the invention may be more fully understood, the following examples are given by way of illustration only.
Example 1
An aqueous anodisation electrolyte containing 0.1 wt.% of aspartic acid and partially neutralised with ammonium hydroxide was compared with: (a) a conventional 0. 1 wt.% ammonium dihydrogen phosphate (ADP) anodisation electrolyte; (b) a 0.1 wt.% ammonium adipate electrolyte; and (c) a 0.1 wt.% ammonium citrate electrolyte.
Electropolished aluminium foil was anodised 2 GB 2 156 852A 2 to 1 OOV at a constant current density of 1 mA/ CM2 at a temperature of WC in all four electrolytes. The % increases in the capacitance of the resulting surface layers of oxide in the adipate, citrate, and aspartate electrolytes relative to the conventional ADP electrolyte were 17.9%, 25.3%, and 41.5%, respectively. The ratios of formation charges required for anodisation in the adipate, citrate, and aspartate electrolytes to that required by the conventional ADP electrolyte were 0.97, 1.52, and 1.10, respectively. Thus, the aspartate electrolyte produced the highest capacitance, while still giving efficient oxide forma- tion.
This work was then extended to etched aluminium foil. The etched foil was anodised to 1 0Ov at a constant current of 1.5A at a temperature of WC in all four electrolytes.
The best results were obtained at a pH of from 5.7 to 7.6 and for the aspartate electrolyte were as follows: at pH 5.7, 41.81tF capacitance and 0. 1 596gA leakage current; at pH 6.6, 43.8gF and 0. 1 523gA; and at pH 7.6, 41.9juF and 0. 13 5OgA. The capacitance and leakage current obtained using the con ventional ADP electrolyte were 29.6gF and aspartate 0. 11 56gA. The % improvements in capacitance in the adipate, citrate and aspar tate electrolytes over the conventional electro- 95 lyte were 41.2%, 48.0%, and 41.6%, re spectively.
A series of experiments established an opti mum pH range for the aspartate electrolyte of 5.5 to 8.5, preferably 5.7 to 7.6 as shown above. At pH values above and below this range, the resulting capacitance was reduced.
The aspartate electrolyte gave satisfactory results at temperatures of from 2WC to its boiling point (approximately 1 OWC for an aqueous solution), but the lower temperatures were more difficult to control, particularly with the exothermic anodisation reaction. It was therefore desirable to optimise the process at a higher temperature, namely about WC, where local overheating has little effect on product quality and the anodising time is suitable for integration of the process into existing manufacturing sequences.
Another series of experiments established that the best results were obtained when the amino acid concentration in the aspartate electrolyte was in the range of 0.05 to 5 wt.%, more preferably 0.1 to 3.5 wt.%.
The glycol electrolyte had a pH of 8.4, a resistivity of 670 S?,cm, and maximum formation voltages of 200v at 25C and 150v at 85'C. the properties of the glycol electrolyte make it suitable for a 1 00v capacitor and the DMF electrolyte is suitable for 200v service.
By varying the nature of the solvent and the amount of the solute, a variety of fill electrolytes may be prepared which are suitable for a range of anodisation voltages and operating temperatures.
Example 2
Two fill electrolytes were prepared using N,N-dimethylformamide and ethylene glycol as the solvents. Each contained 8.1 wt.% of aspartic acid, 4.5 wt.% diethylamine and 6.5 wt.% of water, the balance being dimethylformamide and ethylene glycol respectively. The DMF electrolyte had a pH of 7.4, a resistivity of 27802-cm and maximum formation voltages of 350v at 25'C and 275v at WC.
Claims (17)
1. An electrolyte for use in the anodisation of aluminium and/or as an operating electrolyte for aluminium electrolytic capacitors, which comprises an amino acid and a base dissolved in a solvent and having a pH of from 5.5 to 8.5.
2. An electrolyte according to claim 1, in which the amino acid is a 2amino acid.
3. An electrolyte according to claim 2, in which the 2-amino acid is a dicarboxylic acid.
4. An electrolyte according to claim 3, in which the amino acid is glutamic acid or aspartic acid.
5. An electrolyte according to any of claims 1 to 4, in which the solvent is an organic electrolytic capacitor solvent.
6. An electrolyte according to claim 5, in which the solvent is ethylene glycol or N,Ndimethylformamide.
7. An electrolyte according to claim 6, in which the base is ammonia or an amine.
8. An electrolyte according to any of claims 1 to 7, in which the concentration of the amino acid is from 5 to 10 wt.%.
9. An electrolyte according to any of claims 1 to 4, in which the solvent is water.
10. An electrolyte according to claim 9, in which the base is sodium hydroxide, potassium hydroxide, ammonia, or an amine.
11. An electrolyte according to claim 10, in which the amine is ethylamine, diethylam- ine, or triethylamine.
12. An electrolyte according to any of claims 9 to 11, in which the concentration of the amino acid is from 0.05 to 5 wt.%.
13. An electrolyte according to claim 12, in which the concentration of the amino acid is from 0. 1 to 3.5 wt.% and the pH is 6.6.
14. A process for the electromechanical anodisation of aluminium, which comprises applying an anodising voltage to the alumi- nium whilst it is immersed in an electrolyte as claimed in any of claims 1 to 13, at a temperature of from 25' to 1 OWC in order to form a dielectric layer of oxide on the surface of the aluminium.
15. A process according to claim 14, in which the aluminium is aluminium electrolytic capacitor foil, the dielectric layer of oxide is at least partially crystalline, and the concentra tion of amino acid in the electrolyte is from 0.05 to 5 wt.%.
3 GB 2 156 852A 3
16. A process according to claim 14 or 15, in which the temperature is 85T, the pH is 7, the amino acid is aspartic acid, and the concentration of amino acid in the electrolyte is from 0. 1 to 3.5 wt.%.
17. An electrolyte according to claim 1 substantially as herein described in either of the Examples.
Printed in the United Kingdom for Her Majesty's Stationery Office, Dd 8818935, 1985, 4235. Published at The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/595,883 US4715936A (en) | 1984-04-02 | 1984-04-02 | Process for anodizing aluminum for an aluminum electrolytic capacitor |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8508118D0 GB8508118D0 (en) | 1985-05-01 |
| GB2156852A true GB2156852A (en) | 1985-10-16 |
| GB2156852B GB2156852B (en) | 1988-02-10 |
Family
ID=24385099
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08508118A Expired GB2156852B (en) | 1984-04-02 | 1985-03-28 | Electrolyte for anodisation of aluminium or for electrolytic capacitors |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4715936A (en) |
| JP (1) | JPS60224797A (en) |
| CA (1) | CA1236422A (en) |
| GB (1) | GB2156852B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4975806A (en) * | 1989-05-17 | 1990-12-04 | Aerovox M | Electrolytic capacitor and electrolyte therefore |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0778280B2 (en) * | 1988-07-28 | 1995-08-23 | 株式会社日立製作所 | Metal anti-corrosion surface treatment method |
| JPH0782968B2 (en) * | 1988-08-03 | 1995-09-06 | 信英通信工業株式会社 | Method for manufacturing electrode foil for aluminum electrolytic capacitor |
| JPH0285826A (en) * | 1988-09-22 | 1990-03-27 | Hitachi Ltd | Display panel |
| US6475368B2 (en) | 2001-03-07 | 2002-11-05 | Kemet Electronics Corporation | Method of aqueous anodizing aluminum substrates of solid capacitors |
| US6562652B2 (en) | 2001-06-06 | 2003-05-13 | Kemet Electronics Corporation | Edge formation process with anodizing for aluminum solid electrolytic capacitor |
| US6548324B2 (en) | 2001-06-06 | 2003-04-15 | Kemet Electronics Corporation | Edge formation process without anodizing for aluminum solid electrolytic capacitor |
| US20040140221A1 (en) * | 2003-01-21 | 2004-07-22 | Kinard John Tony | Method of anodizing aluminum utilizing stabilized silicate solutions |
| CN1870863B (en) * | 2005-05-28 | 2011-06-08 | 鸿富锦精密工业（深圳）有限公司 | Casing of portable electronic device and its manufacturing method |
| US20080265218A1 (en) * | 2007-04-24 | 2008-10-30 | Lifchits Alexandre D | Composite layer and method of forming same |
| US8609254B2 (en) | 2010-05-19 | 2013-12-17 | Sanford Process Corporation | Microcrystalline anodic coatings and related methods therefor |
| US8512872B2 (en) | 2010-05-19 | 2013-08-20 | Dupalectpa-CHN, LLC | Sealed anodic coatings |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3773631A (en) * | 1970-10-16 | 1973-11-20 | Blasberg Gmbh & Co Kg Friedr | Aqueous electrolytic bath for coloring anodic oxide layers on aluminum and aluminum alloy substrates and process for coloring said substrates |
| GB1359770A (en) * | 1971-05-18 | 1974-07-10 | Isovolta | Method of anodising parts or objects consisting entirely or partly of aluminium or aluminium alloys |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA755557A (en) * | 1967-03-28 | F. G. Chesnot Bernard | Electrolytes and electrolytic capacitors | |
| US1266557A (en) * | 1916-05-03 | 1918-05-21 | Westinghouse Electric & Mfg Co | Film-forming electrolyte. |
| US2122392A (en) * | 1934-09-10 | 1938-06-28 | Sprague Specialties Co | Electrolytic device |
| US2166180A (en) * | 1935-03-09 | 1939-07-18 | Ruben Samuel | Electrolytic condenser |
| US3524799A (en) * | 1969-06-13 | 1970-08-18 | Reynolds Metals Co | Anodizing aluminum |
| US4152221A (en) * | 1977-09-12 | 1979-05-01 | Nancy Lee Kaye | Anodizing method |
-
1984
- 1984-04-02 US US06/595,883 patent/US4715936A/en not_active Expired - Fee Related
-
1985
- 1985-02-14 CA CA000474293A patent/CA1236422A/en not_active Expired
- 1985-03-28 GB GB08508118A patent/GB2156852B/en not_active Expired
- 1985-04-02 JP JP60068630A patent/JPS60224797A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3773631A (en) * | 1970-10-16 | 1973-11-20 | Blasberg Gmbh & Co Kg Friedr | Aqueous electrolytic bath for coloring anodic oxide layers on aluminum and aluminum alloy substrates and process for coloring said substrates |
| GB1359770A (en) * | 1971-05-18 | 1974-07-10 | Isovolta | Method of anodising parts or objects consisting entirely or partly of aluminium or aluminium alloys |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4975806A (en) * | 1989-05-17 | 1990-12-04 | Aerovox M | Electrolytic capacitor and electrolyte therefore |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60224797A (en) | 1985-11-09 |
| CA1236422A (en) | 1988-05-10 |
| GB8508118D0 (en) | 1985-05-01 |
| GB2156852B (en) | 1988-02-10 |
| US4715936A (en) | 1987-12-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 746 | Register noted 'licences of right' (sect. 46/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |